Traditional skin grafting is accomplished by taking a thin slice of dermal tissue from a donor site in order to cover a wound site, such as a bum area. In some instances, the slice of dermal tissue is meshed to expand its size, creating a meshed graft. Traditional devices used to harvest the tissue from the donor site include dermatomes, which function in many respects similar to a cheese slicer.
Traditional meshed grafting techniques have been shown to yield 90% viability at the donor site. A slightly lower viability rate occurs for non-meshed sheet grafts, mostly due to fluid accumulation under the sheet graft. Factors that lead to graft failure include poor circulation, unclean wounds, patient interference with the graft dressing, obesity, and smoking. Additionally, in at least approximately 10% of cases, infection at the donor site occurs. Although such donor site infections are not likely related to graft failure at the wound site, they still pose problems for both the patient and caregiver.
Traditional meshing techniques yield a most favorable expansion ratio of 6:1. (for example a 1 cm2 donor site can cover a 6 cm2 wound site). While greater ratios of 9:1 and 12:1 are certainly possible, there is also a significant delay in epithelialization with such ratios.
Micro grafting techniques, in which the donor tissue is actually minced in order to achieve a greater than 10:1 expansion ratio, are known in the art. Such techniques allow for a much greater coverage area from a small donor site. However, traditional techniques are cumbersome, and often the viability of the cells is compromised to such an extent that sometimes less than 50% of the cells are viable when applied to the wound site.
It is therefore an object of this invention to provide a simpler grafting procedure, improve micro-graft viability (“take”), reduce the bio-burden at the wound site by better preparation of the wound bed prior to grafting, improve the cosmetics of grafts as compared to meshed grafts, and reduce the size of the donor site.
Additional objects of the present invention include a significant reduction in the size of the donor site as compared to traditional mesh-graft procedures; minimizing scarring of the graft site as compared to traditional mesh-graft procedures; improvement of the pliability of tissue in the graft site; improvement of the cosmetic appearance of the graft site as compared to current methods; and improvement of graft “take.”
It is still a further object of this invention to provide a grafting technique that does not extend the healing time as compared with traditional mesh-grafts, while also reducing the cost and time required to complete the procedure.